Method of making packing rings



y 1946. A. SANDOW ET Al. 7 Y 5 METHOD OF MAKING PACKING RINGS Filed Feb. 11, 1945 IN V EN TORS .Sfl/VDOW ,9. WEA/ZEL ATTORNEY Patented July so, 1946 2,404,864 METHOD OF MAKING PACKING RINGS Abraham Sandow, Plainfield, and Albert A. Wenzel, West Orange, N. J.

Application February 11, 1943, Serial No. 475,504

3 Claims.

This invention relates to a method of makin packing rings, and more particularly to rings which have an inherent resiliency tending to contract the same.

Generally speaking, it has been common practice to construct and use packing rings which have an inherent resiliency tending to expand the rings. When such rings are used in internal combustion engines, for instance, it is necessary to mount them in grooves in the piston so they will expand into contact with the cylinder wall. That in turn necessitates a wall thickriess for the piston which permits cutting the groove therein and still leave a suflicient amount of metal at the base ofthe groove to afford requisite strength to the piston. The greater part of the piston therefore has considerable more thickness than is required. from the standpoint of strength, and the extra thickness means additional weight, to which must be added the weight of the rings, in calculation of inertia developed in the reciprocal movement of the piston. This inertia may be very materially reduced by the expedient of providing a thin and smooth-wall piston, and situate the rings in the wall of the cylinder in appropriate grooves. That necessitates, however, that the rings must have an inherent contracting resiliency and be perfect circles in the contracted position. While some attempts have been made to construct contracting rings, difiiculties have been encountered in casting, tensioning and shaping the same, and these difliculties, until now, have prevented adoption of contracting rings for use in internal combustion engines.

In the broadest aspects of the invention, therefore, an object thereof is to overcome the diificulties of manufacture encountered in construction of a contracting ring.

Another object of the invention is to obtain a method of making a contracting ring which will have perfect shape of a circle at piston diameter but a further tendency to contract when at piston diameter Yet another object of the invention is to avoid operations which would disturb or change the given circular shape of the ring.

' A further object of the invention is to adapt the manufacturing process to correspond as near possible to present-day manufacture of expanding rings.

Again, an object of the invention is to require a minimum of finishin operations.

Yet again, an object of the invention is to employ finishing operations which are of simple character and readily performed.

tern blank with one end sprung to overlap the Still further objects will appear as the description progresses, both by direct recitation thereof and by implication from the context.

Referring to the accompanying drawing showing one embodiment of the method and one form of butt-end split ring, and in which drawing like numerals of reference indicate similar parts throughout the several views; i,

Figure 1 is a perspective view of a completed contracting ring in accordance with the present invention;

Figure 2 is a perspective view of a cast pot or other tube constituting the stock forring patterns; v v

Figure 3 is a perspective view of a pattern blank as out from the stock;

Figure 4 is a perspective view of the pattern blank being severed to give it the form of a split ring; l

Figure 5 is a perspective view of the split patother; H i i T Figure 6 is an edge view looking toward the overlapped ends and showing the pattern completed by fillet material;

Figure '7 is a plan of a pattern board with several of the pattern rings thereon and gated together with a common sprue;

Figure 8 isa perspective view of one of the cast s Figure 9 is an ed e view of the casting in process of having longitudinal cut made at the overlap region;

Figure 10 is an edge View showing excess end metal being out from the casting; and

Figure 11 is a sectional view of a portion of a piston and of a cylinder, and showing rings in sectional cross section mounted in grooves in the cylinder and in engagement with the piston which slides within the rings and cylinder.

In the specific embodiment of the invention illustrated in said drawing, and referring initially to the method involved, reference numeral 15 designates a pot or other tube constituting one means from which pattern blanks l6 are to be formed. The pattern blanks 'are severed as rings from the pot I5, indication being given by dotted line I! where one pattern blank is to be out off therefrom. Pot I5 is a true cylinder, having outside and inside diameters equal, by a pattern-makers rule, to the dimensions which it is desired that the packing ring shall have. In severing the blank from the pot. the blank is given a thickness between flat faces, also by a pattern-makers rule, either directly when outting or by subsequent grinding, equal to the desired thickness of the packing ring casting to be made from the pattern. Of course over-size allowance may be made for any surfaces corresponding to surfaces of the final ring which are to be ground to size.

After the pattern blank the pct 15, said blank is transversely cut, as by a saw l8 as shown in Figure 4. The pattern blank is then of size and shape desired for the finished ring to be cast, and has normally abutting ends, but devoid of the tension desired in the finished ring. One of the end portions of the pattern ring or blank is now sprung or bent upward from the bottom plane of the ring. The upwardly bent portion may be and is thereupon compressed or slid longitudinally of itself over and longitudinally of the other end portion and:

held compressed with the said end portions overlapping, (see Fig. 5). fill the region beneath the sprung end portion of the ring, as by fillet material l9, as shown done in Figure 6. This operation restores a level bottom to the pattern and also fills the gap between the overlapping end portions.

tion ma be directed to the fact that ample thickness of fillet material is placed between the overlapp ng end portions to allow for a casting thickness thereat to accommodate a saw-cut or sl t when completing the ring from the casting. Addition of this fillet material completes the pattern.

A plurality of patterns, with flat face down, arev appliedto a pattern board 2!] to which they may be pinned or otherwise secured in accordance with usual practice. Gate patterns 2.! connect from the several ring patterns, preferably at the overlapped end portions of each, to a common sprue pattern 22. Usual foundry practice is followed in forming sand or other mold with the pa terns and casting the several rings, of which Figure 8 shows a cast ring as it comes from the foundry.

The next operations on the casting are to cut the overlap and remove excess metal. As indicated .in Figure 9, a saw 23 may be used to cut, at ring thickness from sloping face of the casting, one overla ped end portion from the other, making a slit 24 through the ring as shown in Figure .10 longitudinal of the sloping end portion giving proper thickness thereto. Then, as illustrated by Figure 10, a saw 25 is employed to cut 7 the excess tapering material 26 from the under end of the ring beneath slit 24 after which the ring conforms with and has appearance of the pattern of Figure 5 with overlapping ends, except that said ring now tends to spring to overlapped position of end portions. The sloping or upwardly bent end portion is next forcibly spread lengthwise from the end portion which was cast to slope upward and its end forced into abutting relation to the other end. Thereafter the metal is treatedappropriatel'y to give that end which was cast on the slope a normal tendency to reflat with the rest of the ring. .The treatment is such .as not to disturb the circular condition of the ring .nor the tension in the ring to press the ends into abutting relation. Such treatment may be a forcible bending applied to the metal, by peening, by heat, by a combination of these treatments or otherwise as. found desirable. The ring may finally have its flat I6 is severed from The next operation is to Attenfaces ground and then appears in final form as ring 21 of Figs. 1 and 11 tensioned to contract with its ends 26' abutting.

One use of rings as thus manufactured is to situate the same in grooves 28 cut circumferentialiy in a cylinder wall 29 of an internal combustion engine, and with the inner periphery of the ring 27 in sliding engagement with and constituting a sealing surface with a piston 30. Thus the piston is the only moving part and may be thin-walled, smooth-faced or devoid of grooves and not required to carry the additional weight of the piston rings, thereby reducing inertia to a minimum. Afurther advantage of this example of use of our improved'ring resides in the fact that the'ring or rings will be located farther away from the combustion heat and gases. While this use is illustrative of a beneficial purpose involved in the invention, other uses may be made of rings constructed in accordance with the present disclosure. Furthermore, variations may be made in the performance of the several operations and steps explained above for accomplishment of the construction, purposes and results desired, it being understood that the arbitrarily selected showing of apparatus and procedure shown in the drawing and discussed in thespeci fication is for illustration of the inventive concent of which the drawing and description must of necessity give one specific example.

We claim:

1. A method of manufacturing cast packing rings with inherent contracting tension comprising forming a pattern the size and shape of the desired ring, cutting said pattern and overlapping the ends' thereof, making a casting corresponding to said pattern, slitting the casting in conformity with the overlapping of the pattern, and spreading and flattening the ring with the ends thereof abutting.

. 2. A metnod of manufacturing cast packing rings with inherent contracting tension comprising forming a pattern the size and shape of the desired ring, cutting said pattern and overlapping the ends thereof, making a casting'correspending to said pattern, slitting and cutting the casting to provide overlapping ends in conform ity with the overlapping of the ends of. the. pa tern, and spreading andfiattening the ring with said ends thereof abutting and pressed endwise together.

3. A method of manufacturing cast packing rings with inherent contracting tension comprising forming a pattern ring the size and shape tracting tension from desired ring size, cutting said pattern ring and forcibly overlapping the ends and contracting the pattern ring and securing the overlapped margins together whereby the pattern ring is constituted a contracted. pattern of smaller circumference than the desired packing ring, making a casting corresponding to the said contracted pattern, slitting the casting in conformity with the overlapping of the pattern, and spreading the ring the amount of overlapping of the ends until the ends register and the ring expanded against the inherent tension of the casting and its ends brought into abutment with each other and pressed endwise together under the inherent tension of the ring. ABRAHAM SANDOW. ALBERT A. WENZEL. 

